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1.
ACS Omega ; 8(36): 32520-32525, 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37720799

RESUMO

An essential part for crude oil extraction is flow assurance, being critical to maintain a financially sustainable flow while getting the petroleum to the surface. When not well managed, it can develop into a significant issue for the O&G industry. By heating the fluids, problems with flow assurance, including paraffin deposition, asphaltene, and methane hydrate, can be reduced. Also, as the temperature rises, a liquid's viscosity decreases. Research focusing on the application of magnetic nanoparticles (NPs) in the oil industry is very recent. When magnetic nanofluids are exposed to an alternating magnetic field, the viscosity decreases by several orders of magnitude as a result of the fluid's temperature rising due to a phenomenon known as magnetic hyperthermia. This work focuses on the use of magnetic NPs (9 nm) in heavy crude oil (API 19.0). The frequency and strength of the magnetic field, as well as the characteristics of the fluid and the NPs intrinsic properties all affect the heating efficiency. For all of the experimental settings in this work, the flowloop's temperature increased, reaching a maximum of ΔT = 16.3 °C, using 1% wt NPs at the maximum available frequency of the equipment (533 kHz) and the highest field intensity for this frequency (14 kA/m), with a flow rate of 1.2 g/s. This increase in temperature causes a decrease of nearly 45% on the heavy crude oil viscosity, and if properly implemented, could substantially increase oil flow in the field during production.

2.
Nanoscale ; 11(42): 19842-19849, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31441919

RESUMO

A major challenge exists in the preparation of scaffolds for bone regeneration, namely, achieving simultaneously bioactivity, biocompatibility, mechanical performance and simple manufacturing. Here, cellulose nanofibrils (CNF) are introduced for the preparation of scaffolds taking advantage of their biocompatibility and ability to form strong 3D porous networks from aqueous suspensions. CNF are made bioactive for bone formation through a simple and scalable strategy that achieves highly interconnected 3D networks. The resultant materials optimally combine morphological and mechanical features and facilitate hydroxyapatite formation while releasing essential ions for in vivo bone repair. The porosity and roughness of the scaffolds favor several cell functions while the ions act in the expression of genes associated with cell differentiation. Ion release is found critical to enhance the production of the bone morphogenetic protein 2 (BMP-2) from cells within the fractured area, thus accelerating the in vivo bone repair. Systemic biocompatibility indicates no negative effects on vital organs such as the liver and kidneys. The results pave the way towards a facile preparation of advanced, high performance CNF-based scaffolds for bone tissue engineering.


Assuntos
Regeneração Óssea , Celulose/química , Criogéis/química , Nanofibras/química , Crânio , Alicerces Teciduais/química , Animais , Linhagem Celular , Camundongos , Ratos , Crânio/lesões , Crânio/metabolismo , Crânio/patologia
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